A magnificent second-half performance by City of Derry in which they scored 17 points without reply from Dungannon gave the north west team their first senior cup victory in 118 years.
Dungannon had a great start when their speedy winger Jonathan Davis latched onto a Stephen Bell chip ahead in the first minute to dive over.
Worse followed for Derry when wing forward Dwain Cadwalader drove over from a line out making it 10-0 with only seven minutes gone. A Neill Stewart drive over from a line-up narrowed the scores but an Ashley Blair penalty and Charlie Simpson try left Dungannon 18-5 ahead at the break.
The Derry revival started in the 44th minute when scrum-half Archie Kettyle converted a penalty after a great drive by Chris Budgeon.
The decisive score of the game came in the 53rd minute when number eight Keith Gallick picked up 40 metres out from a scrum. He broke up the blind side through three tackles and then side stepped Jan Cunningham to dive over with Kettyle converting.
CITY OF DERRY: I R Moore; S Mallon, R Beggs, M Beddow, S Smyth; A Kettyle, J Allen; R Millar (Capt), J Carey, O Laverty, R Rolston, M Stewart, K Baldrick, K Gallick. Replacements: C Budgeon for J Allen (41 mins) M Black for K Baldrick (50 mins).
DUNGANNON: J Cunningham; J Davis, A Redpath, A Clarke, M Bradley; A Blair, S Bell; M Brady, A Clarke, J Gamble, C Simpson, K Walker, J Patterson, D Cadwalader, T McWhirter (capt). Replacements: D Millar for M Brady, S Rodgers for A Clarke, J Hastings for D Cadwalader (60 mins).
Referee: Mr D Napier (Ballinahinch RFC)
:quality(70)/cloudfront-eu-central-1.images.arcpublishing.com/irishtimes/YVIRIOZQ35EWRPZXR27KGMO6YU.png)